Let the number of students in the class be n.
Let a be the age of youngest student
∴ a = 8 years
Since the age of the students form an A.P. with common difference 4 months or years.
∴ years
Since the sum of the ages of all the students in the class is 168 years.
∴
n = 16
∵ Number of students cannot be negative. Hence, number of students in the class is 16.
A man deposited Rs. 10,000 in a bank at the rate of 5% simple interest annually. Find the amount in 15th year since he deposited the amount and also calculate the total amount after 20 years.